I agree with you that the film will make money, it's Star Wars. But doesn't it make more sense to release a film when there will be the least amount of competition (especially when four of those competitive films just happen to be from the same company who is distributing Episode VII)? Here, let me use an example.
Summer 2015 Movie Releases -
Avengers: Age of Ultron
Pitch Perfect 2
Tomorrowland
Insidious: Chapter 3
Jurassic World
Inside Out
Ted 2
Terminator: Genisys
Magic Mike: XXL
Minions
Ant-Man
Pan
Point Break Re-Make
Holiday 2015 Movie Releases -
Star Wars Episode VII
Hunger Games Part 2
Peanuts
Kung Fu Panda 3
Mission Impossible V
Do you see where I'm coming from? There is very little competition during the holiday season this upcoming year compared to the summer. Also, lets not forget Star Wars still has the stench of the prequels hovering over it. It's not like a Marvel film where it's had several successful films recently to back it up. As far as JJ goes, I know several hard core Star Trek fans who hated Into Darkness because it lazily took quotes and memorable scenes from the franchise and shoehorned them into what was suppose to be a "re-imagining" of the series.
Finally, did you notice you said there were lines wrapped around the theater for "the three original films"? Funny how you don't include the later three films. It sounds to me like your one of those hard core Star Wars fans who would go see anything related to the series because it has "Star Wars" in the title. That doesn't mean the rest of the world is the same way, especially during the cut-throat time frame of the summer movie season. Again, all I'm trying to point out is it makes more sense to release Star Wars when it has the opportunity to make the most money (which is all Disney really cares about).